Transverse fan assemblies are well known in the art for their unique ability to produce a wide and generally uniform air stream. Transverse fan assemblies typically include axially spaced disc-like members which support a plurality of parallel and elongated fan blades in a cylindrical array. As many as thirty-six fan blades may be arranged in the cylindrical array.
It is common to attach the fan blades to the supporting discs by riveting or welding processes. As will be appreciated, individually riveting one end of a series of blades to a disc and then repeating the riveting process at an opposite fan blade end is a time consuming process which is difficult to automate. In addition to the significant time involved in individually welding the fan blades to the discs, the unavoidable heat effects of a welding process often causes distortion or warpage of the fan blades.
When the fan assembly is used in combination with agricultural equipment, such as combines and the like, the fan blades may encounter rocks and other damaging debris during operation of the equipment. The fan assembly is normally operated at relatively high speeds and the rocks and other debris encountered by the fan blades can and often do bend and/or break the blades. As will be appreciated, broken and/or bent fan blades effect fan performance and overall efficiency of the machine. In addition to the other drawbacks mentioned above, riveting or welding of the fan blades to the disc inhibits individual replacement of the blades. Eventually, the entire fan assembly requires replacement. Replacement of the fan assembly is, of course, a time consuming and costly process.
U.S. Pat. No. 3,816,023 to J. Lyle Shaver discloses a blower wheel wherein one fastening device attaches all the fan blades to a support disc. The fastening device is in the form of an internal retaining ring which wedges against an inner end of all the blades. The retaining ring releasably fits into a locking notch provided on each blade to inhibit the fan blades from axial displacement. To effect fan blade replacement, the retaining ring is radially compressed. Radial compression of the retaining ring removes the ring from the locking notch in a respective fan blade and, thus, permits replacement of the blade.
As will be appreciated, radial compression of the ring likewise removes the retaining ring from engagement with the majority if not all the other fan blades. Accordingly, great care must be taken to assure that the retaining ring is repositioned into each fan blade notch of all the other fan blades of the fan assembly upon replacement of a single fan blade. When as many as thirty-six or more fan blades are arranged in a cylindrical array, it is not difficult to appreciate that a considerable amount of time is involved in replacing a single fan blade with such a proposed design. Moreover, should the suggested retaining ring break during fan operation, all the fan blades will be effected possibly resulting in extended damage to the fan assembly.
Thus, there is a need and a desire for a transverse blower fan assembly which allows for individual fan blade replacement when required and in a minimum amount of time without effecting other blades and without requiring use of special tools and the like.